Particle level indicator

ABSTRACT

An apparatus arranged to indicate the level of particles remaining in a housing. The housing dispenses particles therefrom, and the apparatus senses when the particle level is diminished beneath a preselected level. In this manner, additional particles may be added to the housing when the apparatus indicates that the particles therein are depleted.

1l=l8-75 XR 399209155 United States Patent 1191 [11] 3,9

Whited Nov. 18, 1975 [5 PARTICLE LEVEL INDICATOR 3,578,211 5/1971Coapman et al 222/56 [75] Inventor: Charles A. Whited, Rochester, NY.

[73] Assignee: Xerox Corporation, Stamford, Primary n -Robert R e esConn. Assistant ExaminerHadd Lane Filed: Feb. 1974 ttirneG reggent, 0rFirm-H. Fleischer; J. J. Ralabate; [21] Appl. No.: 446,180

Related US. Application Data [62] Division of Ser. No. 357,995, May 7,1973, Pat. No. [57] ABSTRACT An apparatus arranged to indicate the levelof parti- U-S. Cl. le remaining in a housing The housing dispenses 2222/161 particles therefrom, and the apparatus senses when Int. Cltheparticle level is beneath a preselected [58] Field of Search 222/64 23,66, level. In this manner, additional particles may be 222/161; 73/290 Vadded to the housing when the apparatus indicates that the particlestherein are depleted. [56] References Cited UNITED STATES PATENTS2,111,663 3/1938 Graemiger 222/56 5 Claims, 4 Drawing Figures Sheet 1 of3 3,920,155

US Patent Nov. 18,1975

US. Patent Nov. 18,1975 Sheet20f3 3,920,155

US. Patent Nov. 18, 1975 Sheet30f3 3,920,155

. K /VV/ A F/ 2 pm w PARTICLE LEVEL INDICATOR This is a division ofapplication Ser. No. 357,995, filed May 7, 1973, now US. Pat. No.3,834,806 issued to Whited Sept. 10, 1974.

BACKGROUND OF THE INVENTION This invention relates to anelectrophotographic printing machine, and more particularly concerns anapparatus for indicating the level of particles within a toner particlestorage housing utilized in the development system of theelectrophotographic printing machine.

The process of electrostatographic printing comprises electrographicprinting and electrophotographic printing. In both of the foregoingprocesses, an electrostatic latent image corresponding to an originaldocument to be reproduced is recorded on an image bearing member. Aviewable record is produced by depositing toner particles on theelectrostatic latent image to form a powder image thereof. The foregoingis achieved, in electrophotographic printing, by charging aphotoconductive surface to a substantially uniform potential.Thereafter, a light image of the original document is projected onto thecharged photoconductive surface. The light image dissipates the chargeon the photoconductive surface in the irradiated areas to record anelectrostatic latent image thereon. Electrographic printing differs fromelectrophotographic printing in that the electrostatic latent image iscreated without the use of a photoconductive material. That is,electrophotography requires the use of a suitable photoconductor,whereas electrography does not. The electrophotographic process wasoriginally disclosed in US. Pat. No. 2,297,691 issued to Carlson in1942.

A viewable record of the electrostatic latent image is achieved bycontacting the electrostatic latent image with a developer mix ofcarrier granules and toner particles. Typically, toner particles aredyed or colored thermoplastic particles which are heat settable,

whereas carrier granules are ferromagnetic granules. The toner particlesand carrier granules are triboelec- -trically attracted to one anotherso that the toner particles adhere to the outer surface of the carriergranules. As the developer mix contacts the electrostatic latent image,the greater attractive force thereof causes the transfer and adherenceof the toner particles to the electrostatic latent image. Additionaltoner particles are added to the developer mix as toner particles aredepleted therefrom to maintain uniform image density.

In order to produce an efficient electrostatographic printing machine,it is necessary to conveniently and effectively replenish the tonerparticles used in the formation of copies. This is achieved bydispensing quantities of toner particles from a toner particle storagehousing into the developer mix. However, it is readily apparent that asthe toner particles are dispensed from the storage housing, the supplythereof becomes diminished. Thus, it is advantageous to have anapparatus associated with the storage housing for indicating when thetoner particle supply therein has been substantially depleted. In thisway, additional toner particles may be added to the storage housing tomaintain uniform copy density.

Heretofore, various techniques have been utilized to detect the level oftoner particles in the storage housing. For example, a machine operatormay lower an indicator rod into the storage housing to determine thequantity of toner particles remaining therein. However, a disadvantagein handling toner particles in this manner is the tendency of theparticles, due to their extremely small size, to become airborne whenthe storage housing is opened by the operator. The airborne tonerparticles contaminate the surrounding area, and reduce the efficiency ofthe printing machine as well as dirtying the operator and his clothing.

Another approach is to have a rotatable rod with a planar surfacedisposed in the storage housing. The rod is disposed along thelongitudinal axis of the storage housing and biased by the tonerparticles to a position indicating the presence of toner particles inthe storage housing. However, when toner particles are depleted, the rodrotates to a position indicating the absence of toner particles. Thus,as the toner particles are depleted from the storage housing, the rodrotates indicating that the toner particles therein are depleted beneatha pre-selected level. However, the foregoing type of apparatus does notappear to operate entirely satisfactorily when the storage housing isoscillated about its longitudinal axis. An apparatus of this type isdescribed in co-pending application Ser. No. 266,936 tiled in 1972.

Accordingly, it is a primary object of the present invention to improvethe apparatus indicating toner particle quantity in a storage housingthereof.

SUMMARY OF THE INVENTION Briefly stated and in accordance with thepresent invention, there is provided an apparatus for indicatingparticle quantity in a housing utilized for the storage thereof.

In the present instance, this is accomplished by housing means,vibrating means, sensing means, and detecting'means. The housing meansis adapted to store a supply of particles therein. As the vibratingmeans moves the housing means, particles are dispensed therefrom. Thelevel of particles remaining in the housing means is measured by thesensing means. This is accomplished by mounting the sensing means formovement in the housing means. Only the particles stored in the housingmeans above a pre-selected level contact the sensing means. The movementof the sensing means relative to the housing means is measured by thedetecting means. When the sensing means is in contact with theparticles, it moves in unison with the housing means. Contrawise, whenthe sensing means is spaced from the particles, it moves relative to thehousing means. The movement of the sensing means relative to the housingmeans is measured by the detecting means, thereby indicating that theparticle level is beneath the pre-selected level.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of thepresent invention will become apparent upon reading the followingdetailed description and upon reference to the drawings, in which:

FIG. 1 is a schematic perspective view of an electrophotographicprinting machine embodying the features of the present invention;

FIG. 2 is a sectional elevational view of the FIG. 1 printing machinedeveloper unit having a toner particle storage housing therein;

FIG. 3 is a schematic perspective view of the FIG. 2 toner particlestorage housing incorporating the present invention therein; and

FIG. 4 is a fragmentary view of the apparatus of the present inventionutilized in the FIG. 3 toner particle storage housing.

While the present invention will be described in connection with apreferred embodiment, it will be understood that it is not intended tolimit the invention to that embodiment. On the contrary, it is intendedto cover all modifications, alternatives and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

DETAILED DESCRIPTION OF THE INVENTION With continued reference to thedrawings wherein like reference numerals have been used throughout todesignate like elements, FIG. 1 schematically illustrates a multi-colorelectrophotographic printing machine in which the present invention maybe incorporated. The electrophotographic printing machine depictedschematically in FIG. 1 illustrates the various components utilizedtherein for producing color copies from a colored original document.Although the particle level indicating apparatus of the presentinvention is particularly well adapted for use in the toner particlestorage housing of the electrophotographic printing machine depicted inFIG. 1, it should become evident from the following description that itis equally well suited for use in a wide variety of electrostatographicprinting machines and is not necessarily limited to the particularembodiment shown herein.

The printing machine illustrated in FIG. 1 employs an image bearingmember including a drum having a photoconductive surface 12 secured toand entrained about the circumferential surface thereof. Drum 10 ismounted rotatably within the machine frame (not shown). One type ofsuitable photoconductive material is disclosed in US. Pat. No. 3,255,377issued to Sechak in 1972. As drum 10 rotates in the direction of arrow14, it passes sequentially through a series of processing .stations. Adrive motor (not shown) rotates drum 10 at a predetermined speedrelative to the other machine operating mechanisms. Drum 10 has a timingdisc (not shown) mounted on one end thereof. The timing disc is adaptedto actuate the machine logic so that the various machine operations arecoordinated with the rotation of drum 10. Hence, the machine logiccoordinates the sequence of events at the appropriate processingstations in conjunction with the rotation of drum l0.

Initially, drum 10 moves photoconductive surface 12 through chargingstation A. At charging station A, a corona generating device indicatedgenerally at 16, is disposed in a generally transverse directionextending longitudinally across photoconductive surface 12. Coronagenerating device 16 is adapted to spray ions onto photoconductivesurface 12. This charges photoconductive surface 12 to a relatively highsubstantially uniform potential. Preferably, corona generating device 16is of the type described in US. Pat. No. 2,778,946 issued to Mayo in1957.

After photoconductive surface 12 is charged to a substantially uniformpotential, drum 10 rotates to exposure station B. At exposure station B,a color filtered light image of the original document is projected ontothe charged photoconductive surface. Exposure station B includes amoving lens system, generally designated by the reference numeral 18,and a color filter mechanism, shown generally at 20. One type ofsuitable moving lens system is disclosed in US. Pat. No. 3,062,108issued to Mayo in 1962, and a suitable color filter 4 mechanism isdescribed in co-pending application Ser. No. 830,282 filed in 1969.Referring once again to FIG. 1, an original document 22, such as a sheetof paper, book, or the like, is placed face down upon transparentviewing platen 24. Filter mechanism 20, lens 18 and lamp assembly 26 aremoved in a timed relation with drum 10 to scan successive incrementalareas of original document 22 disposed upon platen 24. This creates aflowing light image of original document 22 which is projected ontophotoconductive surface 12. Filter mechanism 20 is adapted to interposeselected color filters into the optical light path. The appropriatecolor filter operates on the light rays passing through lens 18 torecord an electrostatic latent image on photoconductive surface 12corresponding to a preselected region of the electromagnetic wavespectrum, hereinafter referred to as a single color electrostatic latentimage.

After the charged photoconductive surface 12 has been exposed to afiltered light image, drum 10 rotates the single color electrostaticlatent image recorded thereon to development station C. Three developerunits, generally indicated by the reference numerals 28, 30 and 32,respectively, are disposed at development station C. One of theforegoing developer units, i.e. developer unit 28, will be describedhereinafter in greater detail with reference to FIG. 2. However, asuitable development station having a plurality of developer units isdisclosed in US. Pat. No. 3,854,449, issued to Davidson in 1974.Preferably, the developer units are all of a type referred to generallyas magnetic brush developer units. A typical magnetic brush developerunit includes a magnetizable developer mix comprising carrier granulesand toner particles therein. The developer mix is continually broughtthrough a directional flux field to form a brush thereof. Theelectrostatic latent image recorded on photoconductive surface 12 isdeveloped by bringing the brush of developer mix into contact therewith.Each of the respective developer units contain discretely colored tonerparticles corresponding to the complement of the spectral region of thewave length of light transmitted through filter 20, e.g. a greenfiltered electrostatic image is rendered visible by depositing greenabsorbing magenta toner particles thereon, whereas blue and red latentimages are developed with yellow and cyan toner particles, respectively.

[Drum 10 is next rotated to transfer station D where the toner powderimage adhering electrostatically to photoconductive surface 12 istransferred to a sheet of final support material 34. Final supportmaterial 34 may be, amongst others, a sheet of paper or a sheet ofpolysulfone thermoplastic material. A transfer roll, shown generally at36, recirculates support material 34 and is electrically biased to apotential of sufficient magnitude and polarity to attractelectrostatically toner particles from the latent image recorded onphotoconductive surface 12 to support material 34. Transfer roll 36rotates in the direction of arrow 38 in synchronism with drum 10.Preferably, transfer roll 36 and drum 10 are rotated at the same angularvelocity. Inasmuch as support material 34 is secured releasably totransfer roll 36, it moves in a recirculating path therewith. 51" hispermits successive toner powder images to be transferred from theelectrostatic latent image recorded on photoconductive surface 12 tosupport material 34 in superimposed registration with one another.Support material 34 is advanced from a stack 40 disposed on tray 42.Feed roll 44, operatively associated with retard roll 46, advances andseparates the uppermost sheet from stack 40 disposed on tray 42. Theadvancing sheet moves into chute 48 which directs it into the nipbetween register rolls 50. Thereafter, gripper fingers 52, mounted ontransfer roll 36, secure releasably thereon support material 34 formovement in a recirculating path therewith. After a plurality of tonerpowder images have been transferred to support material 34, gripperfingers 52 space support material 34 from transfer roll 36. Stripper bar54 is then interposed between support material 34 and transfer roll 36.Support material 34 is separated from transfer roll 36 and advanced onendless belt conveyor 56 to fixing station E.

At fixing station E, fuser 58 coalesces the multilayered transferredtoner powder image to support material 34. One type of suitable fuser isdescribed in US. Pat. No. 3,498,592 issued to Moser et al. in 1970. Uponcompletion of the fixing process, support material 34 is advanced byendless belt conveyors 60 and 62 to catch tray 64 for subsequent removaltherefrom by the machine operator.

After the transfer process, residual toner particles remaining onphotoconductive surface 12 are cleaned therefrom. The residual tonerparticles are removed from photoconductive surface 12 as it passesthrough cleaning station F. At cleaning station F, a cleaning coronagenerating device (not shown) initially neutralizes the electrostaticcharge remaining on photoconductive surface 12 and the toner particles.The neutralized toner particles are then cleaned from photoconductivesurface 12 by a rotatably mounted fibrous brush 66. A suitable brushcleaning device is described in U.S. Pat. No. 3,590,412 issued toGerbasi in 1971. Brush 66 is positioned at cleaning station F andmaintained in contact with photoconductive surface 12. Thus, after eachsuccessive transfer operation, residual toner particles remaining onphotoconductive surface 12 are removed therefrom.

Referring now to FIG. 2, there is shown one developer unit, i.e.developer unit 28, in detail. Developer unit 28 is depicted in asectional elevational view to indicate more clearly the variouscomponents utilized therein. Only developer unit 28 has been describedin detail as developer units and 32 are substantially identical thereto.The developer units are distinguishable from one another by the color ofthe toner particles contained therein and by the geometrical differencesdue to the angle of mounting. Developer units 28 may have yellow tonerparticles therein, unit 30 magenta toner particles, and unit 32 cyantoner particles.

The major components of developer unit 28 are developer housing 68,paddle wheel 70, transport roll 72, developer roll 74 and housing meansor a toner particle storage housing, indicated generally at 76. Paddlewheel 70 includes a rotary driven hub member 78 with buckets or scoops80 spaced substantially equally about the periphery thereof. As paddlewheel 70 rotates, developer mix 82 is elevated from the lower region ofdeveloper housing 68 to the upper region thereof. In operation, clutchgear 84 meshes with gear 86 secured to paddle wheel 70. Gear 84 rotatesin the direction of arrow 88 driving gear 86 in the direction of arrow90, thereby rotating paddle wheel 70 in the direction of arrow 90. Whendeveloper mix 82 reaches the upper region of developer housing 68, it islifted from paddle wheel buckets 80 to transport roll 72. Alternatebuckets of paddle wheel 80 have apertures therein so that the developermix carried in these areas falls back to the lower regions of developerhousing 68.

As the developer mix falls to a lower region of developer housing 68, itcascades over shroud 92 which is of a tubular configuration with anaperture 94 in the lower region thereof. Developer mix 82 isrecirculated so that the carrier granules thereof are continuallyagitated to mix with fresh toner particles. This agitation generates astrong triboelectric charge to attract the toner particles to thecarrier granules. As developer mix 82, in the paddle wheel bucketsapproaches transport roll 72, the magnetic field generated by fixedmagnets 96 attract developer mix 82 thereto. Transport roll 72 movesdeveloper mix 82 in an upwardly direction. If a surplus of developer mix82 is furnished, metering blade 98 controls the amount of developer mix82 carried over the top of transport roll 72. Metering blade 98 shearssurplus developer mix 82 from transport roll 72. The surplus developermix falls in a downwardly direction toward paddle wheel 70.

The developer mix which passes metering blade 98 is carried overtransport roll 72 and attracted to developer roll 74 by the magneticfield generated by fixed magnets 100 therein. Developer roll 74 movesdeveloper mix 82 into development zone 102 located betweenphotoconductive surface 12 and developer roll 74. The electrostaticlatent image recorded on photoconductive surface 12 is developed bycontacting the moving developing mix 82, i.e. the charged areas ofphotoconductive surface 12 electrostatically attract the toner particlesfrom the carrier granules of developer mix 82. At the exit ofdevelopment zone 72, the strong magnetic field in the directiongenerally tangential to developer roll 74 continue to secure theretoresidual developer mix and denuded carrier granules, i.e. carriergranules lacking toner particles. Upon passing from the developmentzone, the residual developer mix and denuded carrier granules enter aregion relatively free from magnetic forces and fall from developer roll74 in a downwardly direction into the lower region of developer housing68. As the residual developer mix and denuded carrier granules descend,they pass through mix ing baffle 104 which directs the flow from theends toward the center of developer housing 58 to provide mixing in thisdirection.

Shroud 92 controls the fall of the surplus developer mix and denudedcarrier granules so that they mix with the toner particles, rather thansimply falling into the lower region of developer housing 68.Furthermore, shroud 92 isolates, from the developer mix, an interiorcylindrical enclosure in which toner particle storage housing 76 islocated. Toner particle storage housing 76 contains a fresh supply oftoner particles 106 which pass through aperture 94 in shroud 92 and intothe stream of developer mix 82. Adding toner particles at this locationinsures that they cannot be carried into development zone 102 withoutsome degree of mixing with the denuded carrier granules. Additionaltoner particles are added to the developer mix in order to replace thoseused in forming toner powder images on the copies. This maintains theconcentration of toner particles in the developer mix substantiallyconstant providing substantially uniform image density.

The apparatus of the present invention, shown generally at 108,indicates the level of toner particles remaining in toner particlestorage housing 76. Oscillation of toner particle storage ho using 76about the longitudinal axis thereof dispenses toner particles therefrom.This is achieved by an oscillator motor (not shown) adapted to vibratetoner particle storage housing 76 substantially '7 about thelongitudinal axis thereof.

Turning now to FIG. 3, the detailed structural configuration of tonerparticle storage housing 76is shown therein. As shown in FIG. 3, tonerparticle storage housing 76 includes a tubular member 110 having asupply of toner particles 106 therein corresponding in color to thatrequired by the respective developer unit. Tubular member'l10 includes aperforated region 112 therein. When tubular member 110 is stationary,toner particles 106 form a bridge over the holes in perforated region112 and are not dispensed therethrough. However, when tubular member 110is oscillated about the longitudinal axis thereof this bridging effectis broken causing toner particles 106 to pass through perforated region112 and into the lower region of developer housing 74. Preferably,tubular member 110 may be molded from a suitable plastic material withperforated region 112 comprising a plurality of substantially parallelequally spaced slots 115 therein.

Sensing means, indicated generally at 114, has a portion thereof incontact with toner particles 106. Under these circumstances, sensingmeans 114 oscillates in unison with tubular member 110. Sensing means114 includes a shaft member 1 16 mounted pivotably at end portion 118 onend plate 120 of tubular member 110. A generally planar member or plate122 is mounted on the other end region 124 of shaft 116. When planarmember 122 is spaced from toner particles 106, shaft member 116oscillates relative to tubular member 110. The movement of planar member122 relative to tubular member 1 is sensed by detecting means, indicatedgenerally at 126. Detecting means 126 senses the movement of platemember 122 relative to tubular member 110. The detailed structuralconfiguration of detecting means 126 will be described in conjunctionwith FIG. 4. Circuit means, indicated generally at 128 develops anelectrical output signal in response to detecting means 126 indicatingthat planar member 122 is oscillating relative to tubular member 110.

Turning now to FIG. 4, there is shown the detailed structuralconfiguration of the level indicating apparatus 108 of the presentinvention. As shown therein, detecting means 126 includes a suitablemagnetic sensor or pick-up 130 adapted to sense the movement of planarmember 122 relative to tubular member 110. By way of example, a suitablemagnetic pick-up 130 is preferably Model No. 340-001 manufactured byAirpax Electronic Company, Fort Lauderdale, Fla. If a sub-miniaturemagnetic pick-up 130 is required, Model No. 10024 may be suitable.

Magnetic pick-up 130 is mounted in door 121 of developer unit 28. Themovement of tubular member 110 and planar member 122, in unison with oneanother, is detected, as well as the relative movement therebetween.Thus, magnetic pick-up 130 senses the movement of planar member 122 whenit contacts toner particles 106. Circuit means 128 is set such that thelow level display is not energized when magnetic pick-up 130 senses themovement of planar member 122 in unison with tubular member 1 10.However, circuit means 128 triggers the low level display when planarmember 128 vibrates relative to tubular member 110, i.e. when planarmember 128 no longer contacts toner particles 106. This permits tubularmember 110 to be discarded when toner particles 106 are depleted beneaththe preselected level, while permitting magnetic pick-up 103 to re-usedfor successive tubular members 110.

8 Shaft member 116 and planar member 122 are preferably made from asuitable metallic material adapted to cut the lines of flux generated bymagnetic pick-up 130. Cutting the lines of flux produced by magneticpick-up 130 generates an electrical output signal which, in turn, issuitably processed by circuit means 128. Circuit means 128 maypreferably be a suitable discriminator circuit adapted to produce anelectrical output signal when the signal from magnetic pick-up 130 isabove a predetermined level. The electrical output signal fromdiscriminator circuit 128 is arranged to actuate suitable display means(not shown) such as a buzzer or light panel indicating that the tonerparticle level in tubular member is beneath the preselected level.Thereupon, the printing machine may de-activate automatically permittingthe operator to replace the empty tubular member 110 with one containingtoner particles.

In recapitulation, it is apparent that the apparatus of the presentinvention is arranged to oscillate with the tubular member when thetoner particle level therein is above a pre-selected level. However, theappara of the present invention oscillates relative to the tubularmember when the toner particle level is beneath the preselected level.The oscillation of the Si using "@8118 relative to the tubular member isdetected and an electrical output signal developed by the circuit rneanswhich, in turn, actuates a suitable display and de-energize the printingmachine. The display indicates that the toner particle level in thetubular member is beneath the pre-selected level. Hence, the machineoperator is advised that the toner particle level is low and thatadditional toner particles are required in order to produce satisfactorycopies within the electrophotographic printing machine.

It is, therefore, evident that there has been provided in accordancewith this invention, an apparatus for detecting the level of tonerparticles in a toner particle storage housing that fully satisfies theobjects, aims and advantages set forth above. While this invention hasbeen described in conjunction with specific embodiments thereof, it isevident that many alternatives, modifications and variations will beapparent to those skilled in the art. Accordingly, it is intended toembrace all alternatives, modifications and variations that fall withinthe spirit and broad scope of the appended claims.

What is claimed is: 1. An apparatus for indicating particle quantity,including:

means for housing a supply of particles, said housing means includes agenerally tubular member journaled for oscillatory movementsubstantially about the longitudinal axis thereof and defining a chamberfor storing a quantity of particles therein, said tubular member havinga perforated region arranged to prevent the passage of particlestherethrough when said tubular member is stationary while allowing thepassage of particles therethrough when said tubular member isoscillated;

means for vibrating said housing means to dispense particles therefrom;

means for sensing the level of particles remaining in said housingmeans, said sensing means being mounted for movement in said housingmeans and arranged to engage the particles stored therein above apre-selected level; and

9 means for detecting the movement of said sensing means relative tosaid housing means, said sensing means being adapted to move relative tosaid housing means when the particles stored therein are beneath thepre-selected level and said vibrating means moves said housing means todispense particles therefrom.

2. An apparatus as recited in claim 1, further includ- .ing:

4. An apparatus as recited in claim 3, wherein said sensing meansincludes:

a shaft member having one end portion thereof mounted pivotably in saidtubular member, said shaft member extending in a direction substantiallynormal to the longitudinal axis of said tubular member; and

a generally planar member secured to said shaft member in the region ofthe other end portion thereof, said planar member moving substantiallyin unison with said tubular member when contacting the particles storedtherein, and oscillating relative to said tubular member when spacedfrom the particles stored therein.

5. An apparatus as recited in claim 4, wherein said detecting meansincludes magnetic sensing means mounted closely spaced to said tubularmember in communication with said planar member sensing the oscillationthereof relative to said tubular member for indicating that said planarmember is spaced from the particles therein and that the particles arebeneath the pre-selected level.

1. An apparatus for indicating particle quantity, including: means forhousing a supply of particles, said housing means includes a generallytubular member journaled for oscillatory movement substantially aboutthe longitudinal axis thereof and defining a chamber for storing aquantity of particles therein, said tubular member having a perforatedregion arranged to prevent the passage of particles therethrough whensaid tubular member is stationary while allowing the passage ofparticles therethrough when said tubular member is oscillated; means forvibrating said housing means to dispense particles therefrom; means forsensing the level of particles remaining in said housing means, saidsensing means being mounted for movement in said housing means andarranged to engage the particles stored therein above a pre-selectedlevel; and means for detecting the movement of said sensing meansrelative to said housing means, said sensing means being adapted to moverelative to said housing means when the particles stored therein arebeneath the pre-selected level and said vibrating means moves saidhousing means to dispense particles therefrom.
 2. An apparatus asrecited in claim 1, further including: circuit means arranged to producean electrical signal in response to said detecting means indicatingmovement of said sensing means relative to said housing means; anddisplay means, actuated by the electrical signal generated by saidcircuit means, for indicating that the quantity of particles remainingin said housing means is beneath the pre-selected level.
 3. An apparatusas recited in claim 1, wherein said vibrating means includes a motoradapted to oscillate said tubular member about the longitudinal axisthereof.
 4. An apparatus as recited in claim 3, wherein said sensingmeans includes: a shaft member having one end portion thereof mountedpivotably in said tubular member, said shaft member extending in adirection substantially normal to the longitudinal axis of said tubularmember; and a generally planar member secured to said shaft member inthe region of the other end portion thereof, said planar member movingsubstantially in unison with said tubular member when contacting theparticles stored therein, and oscillating relative to said tubularmember when spaced from the particles stored therein.
 5. An apparatus asrecited in claim 4, wherein said detecting means includes magneticsensing means mounted closely spaced to said tubular member incommunication with said planar member sensing the oscillation thereofrelative to said tubular member for indicating that said planar memberis spaced from the particles therein and that the particles are beneaththe pre-selected level.